Abstract 420: Focal Adhesion Kinase Disrupts Nuclear Factor-kB Signaling and Alleviates Atherogenesis

Abstract

Introduction: While we have discovered that focal adhesion kinase (FAK) is critical for global pro-inflammatory gene expression, it remains unclear what role FAK plays in vascular inflammation. Our preliminary data suggested that FAK might regulate a major inflammatory signaling factor, NF-kB. The goals of this study are to investigate the mechanisms underlying FAK-mediated inflammatory gene expression in endothelial cells (ECs), and the effect of FAK inhibition on atherogenesis. Hypothesis: FAK activity is required for pro-inflammatory gene expression via NF-kB activation in ECs. Methods: Human aortic ECs (HAoECs) were treated with TNF-α and with/without a FAK inhibitor (FAK-I). Inflammatory gene expression and NF-kB signaling was evaluated via western blot, immunocytochemistry or qRT-PCR. To access vascular inflammation in vitro , primary mouse monocytes were used in an adhesion assay on TNF-α stimulated HAoECs. To evaluate the importance of FAK activity in atherogenesis, partial carotid artery ligation was performed in ApoE-/- mice. Mice were fed a high fat/high cholesterol diet and were given either FAK-I or vehicle by oral gavage for two weeks. Both carotid arteries were harvested and analyzed. Results: We found that FAK activity is required for expression of various pro-inflammatory molecules such as VCAM-1 and MCP-1, and FAK inhibition blocks sustained NF-kB activation. Mechanistically, while FAK inhibition does not block NF-kB activation after 1hr TNF-α stimulation, NF-kB activity significantly reduced after 3hr when compared to TNF-α only. This decrease in NF-kB activity was correlated with a decrease in NF-kB nuclear localization and an increase in IkB protein stability. FAK inhibition reduced monocyte attachment to TNF-α stimulated HAoECs (3.8 vs 22.1 fold). Mice treated with FAK-I showed decreased VCAM-1 expression, macrophage infiltration and lipid accumulation compared to vehicle group. Conclusion: These results suggest that FAK is critical for global inflammatory gene expression and plays a key role in maintaining sustained NF-kB activity during chronic inflammation in ECs. FAK inhibitors may prove useful as an “anti-inflammatory drug” in the treatment of cardiovascular disease.